MOTORSPORT ENGINEERING
transfer the aerodynamic loads, is made from
prepreg carbon fibre and graphene and is bolted
onto the chassis. The whole unit is as strong and
as light as possible.
BAC made a conscious decision in the early
stages of development to use a spaceframe
chassis in that it provided the maximum flexibility
for development at reasonable cost. If they had
elected to go full carbon from the outset, it would
have been much more difficult to change or modify
the chassis once tooling had been produced. The
spaceframe is only 48kg and an equivalent carbon
chassis would only be about 5% lighter. They
made a far bigger weight saving switching from
fibreglass to carbon fibre for the bodywork.
The spaceframe allows them to ring the changes
in the chassis as the vehicle evolves. Having this
flexibility is important as they accommodate new
engines or modify the bodywork or the cockpit
width as customers require. It is an essential
part of the BAC offering that they provide a fully
customised vehicle tailored exactly to each driver.
BAC had an idea how the product was going to
evolve and how the market was going to react
to it, but having the flexibility to change and fine
tune the chassis was much more important than
locking the development to a full carbon chassis
from the start. The whole vehicle architecture is
futureproofed around this flexible approach. In
addition, the spaceframe chassis is not as fragile
as carbon and is much easier to repair.
The chassis structure is very robust for its light
weight and the torsional stiffness is exactly where it
needs to be.
“We started to have ideas about our own car in
1999,” says Neill Briggs, Co-Founder of BAC
and Director of Product Development. “We had
conversations with racecar manufacturers with
regards to how we could do it – we weren't that
experienced at the time and learned a lot on this
project.”
At the time the market was already seeing cars
with a ‘singularity of purpose’ like the Ferrari F40,
the Renault Spyder, the Lotus 340R and then later
the KTM Xbow – these kinds of vehicles had never
been seen before.
Even the mainstream manufacturers like Ferrari
were producing the 350 Challenge Stradale –
road-going versions of their competition specials
and that trend continues today.
“For us there was clearly a market made up of
high-net-worth individuals who had a focus on
performance driving,” says Briggs. “These people
were attracted to a low-volume, differentiated
product and stimulated by its collectability,
desirability and high residual values.”
It was an opportunity for BAC to take the concept
1 or 2 steps further, in terms of its absolute focus.
“Rather than strip out a supercar to save weight on
something designed to hold 2 people and luggage
to go to the South of France,” says Briggs, “we
started with a single seat and a blank sheet of
paper and designed up from there.”
The BAC design brief was to provide the ultimate
driving experience on the road and the track.
“So the vehicle architecture of only having one
seat was the easiest decision we ever made,”
says Briggs. “Formula cars have developed a
characteristic layout over the last 40 – 50 years
– we’ve taken that layout and racing design and
manufacturing technologies and brought it to the
mainstream.”
The BAC Mono has a single seat and a longitudinal
semi stressed engine. “We never looked at any
other config as that would compromise the
ultimate performance goal,” says Briggs. “The
whole concept is about performance and ultra-light
weight, so another person offset to one side has
a bigger impact on a car that only weighs 600kg
than it would on a car that weighs 1½ tonne.”
The austere ‘stripped down’ sophisticated
mainstream market had already been conditioned
by the Lotus Elise and the Porsche GT3, with bare
chassis members, no carpets, no soundproofing,
no radio and every other creature comfort offered
as an option. And these kinds of cars are selling
very well.
Mono is powered by a longitudinally mounted
2.5-litre, 305 bhp four-cylinder engine built by
Mountune. This engine is bespoke to the Mono,
but it comes from the same family of Ford Duratec
engines that Mountune prepare for the World
Rallycross Championship with a special dry sump
for the Mono. This is coupled to an F-3 spec
6-speed sequential gearbox from Hewland. The
suspension is a fully-adjustable pushrod system
with dampers made by SACHS Racing. It is fitted
with 295mm ventilated discs with AP Racing
calipers.
The Mono weighs just 580kg which gives it a
very healthy power-to-weight ratio of 525 bhp/
tonne, better than hyper cars like the Porsche 918
Spyder and the Bugatti Veyron. This propels it to
60mph in just 2.7 seconds and gives a top speed
of 170mph.
As well as the outright acceleration, the effortless
way the Mono changes direction really sets
it apart from any other road racer. Piloting
it is instinctive and at the limits of adhesion
the appropriate corrective action seems to
be a natural consequence of the slip angle
generated. At the very limit of grip, there’s a hint
of understeer, but for the most part, the Mono is
nicely neutral, making it easy to explore the limits
even for relatively inexperienced racers, without
fear of becoming part of the scenery. Despite its
incredible performance, the Mono is very civilised
around town at ordinary speeds. It rides very well
with the open-wheel suspension design providing
100mm of vertical wheel travel and allowing the
Mono to navigate the worst road bumps and
potholes.
Tyre manufacturer Kumho used their motorsport
and road car experience to develop a special
rubber compound for the Mono, which is
designed to work with the low weight and the
optimised pushrod suspension setup.
20 November 2018